The present invention relates generally to bar code scanners, and, more specifically, to low profile scanners.
In a typical bar code scanner, a laser scan beam traverses a bar code having a sequence of varying width dark bars and white spaces and scatters back into the scanner. A common bar code uses the conventional Uniform Product Code (UPC) convention for encoding data therein. For example, in a merchandising point-of-sale facility, the UPC bar code encodes product description and price information which is read by the scanner at a checkout counter for totaling the cost of merchandise being purchased by a customer.
A typical omni-directional bar code scanner projects a laser beam on a rotating multi-faceted spinner which scans the beam across several pattern mirrors for creating corresponding scan lines which are projected out through a scan aperture or window toward the bar code being manually swiped thereacross. The bars and spaces of the bar code differently scatter light in a return path through the pattern mirrors to the spinner from which it is intercepted by a collection mirror and focused on a photodetector. The photodetector's signal is conditioned, digitized, and decoded in suitable decoding electronics to decode the scattered light for reading the data contained in the bar code.
The various pattern and collection mirrors typically found in a bar code scanner are suitably aligned therein for performing their separate functions and are typically located in different vertical planes which necessarily increases the overall depth or height of the scanner.
In one type of checkout counter, the scanner is mounted in the top of a counter in the form of a table which provides access thereunder for accommodating the legs and knees of an operator in a sitting position. However, conventional scanners cannot be made substantially shallow in depth in view of the required optical paths therethrough for the scan and scattered beams.
Accordingly, it is desirable to have a shallow bar code scanner for reducing the overall thickness of a table checkout counter for providing suitable ergonomics for the operator.